1. Field of the Invention
The present invention relates to a video/audio data transmission through a network and, more particularly, to an intermediate data based video/audio streaming method in which, in the transmission of video/audio data, a server transmits the video/audio data in the form of intermediate data and a client receives and directly processes it without using an additional decompression apparatus, allowing easy video/audio data transfer and simplifying the structure of the client system.
2. Discussion of Related Art
In general, in the transmission of video (moving picture and still picture) data through a network, a transmitting side compresses the video data to be transmitted with various compression methods and then transmit it in view of a limited data transfer rate and the amount of data transmitted in the network. In this case, though the amount of data transmitted is remarkably reduced, a receiving side requires a separate apparatus for receiving the compressed video data and an apparatus for decompressing it, to receive and process the transmitted video data.
FIG. 1 roughly illustrates the configuration of a conventional video/audio data processor, which shows a procedure that a computer opens a video file (JPEG, MPEG-1, MPEG-2, H.261, H.263, and so on) and executes it. Referring to FIG. 1, a data storage 1 stores the video file, and a decoder 2 which consists of a video decoder and audio decoder opens the video file stored in data storage 1, divides it into a video signal and an audio signal and decodes them using respective decoders. That is, the video decoder decodes the divided video signal while the audio decoder decodes the divided audio signal. Further, a video outputting unit 3 outputs the video signal decoded by decoder 2 and an audio outputting unit 4 externally outputs the audio signal decoded by decoder 2.
FIG. 2 roughly illustrates the configuration of a conventional apparatus for video/audio data transmission and reception through a network, usually employed in a general VOD (Video On Demand). Referring to FIG. 2, the apparatus is classified into a server 10 and client 20. Server 10 stores a plurality of video files at a data storage 11 and, when client 20 requests any video file, extracts the corresponding file to transmit it. Client 20 temporarily stores the video data supplied from server 10 at a buffer 21. A decoder 22 sequentially reads the data stored at buffer 21 and divides it into a video signal and an audio signal. Then, decoder 22 decodes the video signal using its inner video decoder and transmits it to a video outputting unit 23, thereby outputting the video data. Further, decoder 22 decodes the audio signal using its inner audio decoder and transfers it to an audio outputting unit 24, thereby accomplishing the output of audio data.
In this conventional media file streaming method, the server transmits the compressed video file itself and the client decompresses the compressed video file. That is, when the client requests a specific video file, the server reads and transmits the file itself. Here, the server simply reads the corresponding compressed file and transfers it to the network without any change. Accordingly, the client needs an additional apparatus for decompressing the compressed file and decoding it to reconstruct the compressed file. This results in complicated configuration of the client. Furthermore, the reception of the compressed file also requires a high-speed central processing unit. Accordingly, the hardware of the client system become difficult to realize and product cost increases.